This invention relates to automated teat dipping systems for dairy animals and more particularly to apparatus and methods for applying dip to a teat by injecting dip into the liner dome at the end of milking, and stopping a milking pulsation in a closed position prior to applying the dip to improve teat coverage before detaching the milker unit.
Dairy milking systems as they relate to the present invention include a cluster of teat cups. Each teat cup receives a flexible liner to define a pulsation chamber between the cup and the liner. A dairy animal teat is disposed inside the liner during milking. Milk flows from the cow through each flexible liner and then through a milk tube to a milker unit collecting device, which collects milk from all of the animal's teats. This combination of elements is known as a milker unit and can be used to milk cows, sheep, goats and other dairy animals. Each milker unit is used to milk multiple animals so it must be sanitized, at least periodically, to prevent transmission of dirt and germs into the milk, and to help prevent transmission of diseases from animal to animal.
To attach the teat cup and liner assembly to a dairy animal teat, vacuum is applied through the milk tube. This vacuum also draws milk from the liner into the milk tube and milk collecting device. Milk is drawn from each teat by applying a pulsation of vacuum and atmospheric pressure to the pulsation chamber defined between the teat cup and the flexible liner. When pulsation is in the “on” position, vacuum is applied to the pulsation chamber and the liner exerts little or no pressure on the teat because it is offset by vacuum inside the liner. In the “off” position, the pulsation chamber is exposed to atmospheric pressure, so vacuum inside the liner causes the liner into massaging contact with the teat. Vacuum inside the liner draws milk from a teat and keeps the teat cup and liner attached to the dairy animal teat and draws milk downstream into collection lines. Pulsating between “on” and “off” alternates between milking and massaging of the teat and assures that the bodily fluids inside the teat do not collect at the end of the teat, hindering the milking process. When milking is done, pulsation ceases and vacuum inside the liner is cut off (at least partially) and the teat cup and liner are detached from the teat.
In a representative system, milk from individual animals flows from each collecting device into a milk line and/or piping system that receives milk from all of the milker units in the dairy. The milk is then chilled and stored in a milk tank. The milk lines and storage systems must not be contaminated with dirt, debris, chemicals, pathogens, or contaminated milk.
After milking, dairy animal teats have broadened milk ducts that make them susceptible to new infection from mastitis pathogens. To combat these pathogens, the teats can be treated with a disinfectant solution that adheres well to the teats and which usually also contains a skin-care component. The application of this disinfectant solution is called dipping and can be done with a hand-held dipping cup into which the individual teats are introduced. Dip can also be applied using manual spray devices and foam applicators. Dipping with a cup is especially labor-intensive, but generally has a better success rate and a lower consumption of dipping solution than manual spraying methods.
Some spraying methods are automated to spray dip from a dipping arm or dipping bar toward teats and udders. Automated sprayers are not precise and tend to consume much more dipping solution than manual dipping methods. Other automatic teat dipping applicator systems applied dip upward from the short milk tube toward the bottom of a teat at the end of milking, but before detachment from the milker unit. This arrangement provided some protection, but it did not coat the entire teat uniformly. See U.S. Pat. No. 7,290,497. Others have suggested automated systems that apply dip to an upper teat portion, but most of these failed to provide: uniform dip coverage on teats; consistent volumes of dip application over time; and protection of downstream milk system components from being contaminated by dip and other chemicals.
Much improved automated dipping systems are disclosed in U.S. Pat. Nos. 8,033,247, 8,117,989, 7,707,966, and 7,401,573, for example. Such systems automate the dipping process by injecting teat dip into the liner and onto the teat before the cluster is removed from the cow. Nonetheless, in most milking and teat dipping systems, the timing of the dipping process and the timing of turning pulsation on and off are not coordinated. So, if the milker unit is removed in a normal pulsation sequence, teat dip coverage might not be adequate because dipping could take place too close to the milker unit removal.
As stated above, a pulsation system alternates between ‘open’ (also called milking position) or ‘closed’ (also called massaging position). Typically, the coverage of teat dip is not as uniform when the liner is in the open position because the teat at the end of milking is relatively flaccid, empty of milk, and has limited contact with the liner wall. Further, the injected dip can easily break what little teat-to-liner contact there is and cause the milker unit to detach quickly and give the dip an exit path past the teat.
Further complicating automated teat dipping is that modern pulsation systems can be alternating pulsation systems having two liners in a single milker unit that are in a closed position while the other two liners in the same milker unit are in open positions, as opposed to simultaneous pulsation systems where all four liners are either open or closed. Without managing the pulsation during the dipping process in alternating pulsation systems, two of the four teats are disadvantaged for proper dip application.
Thus, there is a need for automated teat dip applicators and methods to ensure uniform dip coverage around and along a dairy animal teat.